1. Field of the Invention
The present invention relates to a vehicle lamp and more particularly to an improvement in a vehicle lamp such as a rear combination lamp that has a reflex reflector.
2. Prior Art
Some of rear combination lamps or the like disposed at the rear portion of an automobile or other vehicle are provided with a xe2x80x9creflex reflectorxe2x80x9d having a function of reflecting light that has entered from outside toward the following vehicle, thereby improving visibility of the vehicle.
In many cases, this reflex reflector is formed with, for example, a lens with steps additionally disposed for reflecting light that has entered from outside, further to the outside of the front lens which is disposed so as to block a frontal opening of a lamp chamber housing a light source.
Alternatively, as shown in FIG. 7, a lens 101 is disposed so as to block a lamp chamber 103 which is formed inside of a reflector 106 formed on the inner surface of a parabola-shaped lamp body 107 of a lamp 100. The lens 101 has a concave portion 104 recessed toward a light source 105.. Furthermore, a lens 102 with steps 108 for reflecting light from outside is attached to the concave portion 104 so as to perform a reflex reflector function.
However, the structure of the conventional reflex reflector shown in FIG. 7 has problems. The light Pa emitted from the light source 105 (and light Pb reflected by the reflector 106) is transmitted through the lens 101 and irradiated to a lens disposed as a reflex reflector (hereafter referred to as xe2x80x9ca reflex reflector lens.xe2x80x9d)
Therefore, a heat-resistant synthetic resin material such as polycarbonate (hereinafter referred to as PC) with a heat resistance temperature of 135C also needs to be used for the reflex reflector lens 102, as in the case for the lens 101.
It is unavoidable to use a heat resistant material for the lens 101 disposed in a position opposing the light source 105. In this regard, a heat resistant material needs to be used not only for the lens 101, but also for the lens 102 for the reflex reflector.
In such cases, since a heat resistant synthetic resin material such as PC is more expensive than a material with low heat resistance such as polymethylmethacrylate, a vehicle lamp, particularly the one with a reflex reflector, faces the technical challenge of cost reduction.
Therefore, it is an object of the present invention to reduce the cost of a vehicle lamp by eliminating the necessity for use of a heat resistant material for a reflex reflector lens by devising a lens structure around the reflex reflector.
The above object is accomplished by a unique structure for a vehicle lamp that includes a light chamber formed by a lamp body and a lens; and the unique structure of the present invention is that the vehicle lamp further comprises: a reflex reflector lens which is separately formed from the lens, and a light reflection means or a light reflecting section disposed in a region that is a part of the lens and faces a light source, such a light reflecting means or the light reflection means reflecting light emitted from the light source toward the light source.
Since this light reflection means reflects light from the light source (along with the light reflected by the reflector), no light from the light source is irradiated to the reflex reflector lens. Accordingly, temperature rise in the reflex reflector lens is kept small.
In the above structure, the light reflection means or the light reflecting section is disposed in a region that opposes or faces the light source. In other words, the light reflection means (the light reflecting section) is disposed in a region in front of the light source. Thus, it is possible to reliably reflect the light, which is directly traveling from the light source, toward the light source and to more reliably limit the temperature rise in the reflex reflector lens.
The light reflection means or the light reflecting section is provided in a lens that is an essential component of a vehicle lamp. More specifically, a lens is arranged so as to be interposed between the reflex reflector lens and the light source, and reflective steps are formed in the light reflection means (light reflecting section) that faces the reflex reflector lens. The reflective step portion entirely reflects the light emitted from the light source.
In a more preferable structure, the above reflective step is provided on a surface of the front lens that faces the light source (i.e. on a surface facing the light source) so as to project toward the light source. With this structure, the light emitted from the light source is reflected at a position that is as close as possible to the light source (i.e. a position as far as possible from the reflex reflector lens), thus keeping the temperature rise in the reflector lens as small as possible.
Furthermore, the reflective step is formed with minute cone-shaped steps. By way of arranging a plurality of cone-shaped steps, a reflective effect on the light emitted from the light source can be reliably displayed.
With the above-described structure, the need for using a heat resistance material such as polycarbonate for the reflex reflector lens can be avoided, it is thus possible to use a less costly material such as polymethylmethacrylate or the like. In other words, it is possible to use a material with lower heat resistance than the lens. Consequently, cost reduction for a vehicle lamp that has a reflex reflector lens can be reliably achieved.